The use of winery waste compost to establish cabbage (Brassica oleracea var. capitata L.) and Swiss chard (Beta vulgaris subsp. cycla) on sandy soil at Bien Donné experimental farm near Paarl in the Western Cape region

Abstract

A study was carried out at Bien Donné Experimental Farm, near Paarl in the Western Cape Region (South Africa), to evaluate the performance of solid winery waste compost (WWC) and inorganic fertilizer (N:P:K, 2:3:4 (30) - 5g Zn%) on growth and yield of cabbage (Brassica oleracea var. capitata L.) and Swiss chard (Beta vulgaris subsp. cycla). The experimental plot was fertilized as per treatment with WWC (100% and 400% equivalent recommended fertilizer application using N as reference mineral) and inorganic fertilizer. The experimental design was set up in a Randomized Complete Block Design (RCBD) with 4 treatments (control- without compost and inorganic fertilizers, inorganic fertilizer-2:3:4 (30) - 5g Zn% and LAN (28), WWC application at different application rates were (3485g/plot) (100%) and (13939g/plot) (400%)) replicated four times. Soil analysis showed that the experimental plot is dominated by sandy soil structure. Results of mineral analysis after application of treatments showed a significant (p>0.05) drop in soil pH over time in the untreated control and application of 400% WWC significantly (p<0.05) raised soil pH compared with the control. The application of mineral fertilizer showed significant (p<0.05) increase in soil P compared with the other treatments. However, WWC picked up significant (p<0.05) speed above inorganic fertilizer, thus making P available to the soil than NPK mineral fertilizer. A significant (p<0.05) drop in soil K content by 21% over time on amended soil with inorganic fertilizer treatment was observed. However, the application of WWC at 300 and 400% significantly (p<0.05) raised the soil K by 54.93 and 73.06% respectively. There were no significant differences in soil Ca over time, but high soil Ca concentrations from WWC (100%) were recorded compared to inorganic treatment that showed the lowest soil Ca concentration. There was a slight drop in soil Na over time in control and soil amended with inorganic fertilizer. The effects of the treatment on Mg values were not so prominent, suggesting that concentrations of nutrients are less essential characteristics of the soil or small portion of nutrients were readily available on the soil.